CAMBRIAN AND LOWER ORDOVICIAN. 



145 



In connection with the discussion of the Etcheminian, Walcott*" published 

 the following general classification of Cambrian formations : 



Classification of the Cambrian formations. 



In 1904 Matthew ^^^ published the results of his studies of the Cambrian of 

 Cape Breton. He gives detailed sections and diagrams and presents a revised 

 classification with the following comments : 



In consequence of the finding of trilobites, brachiopods, etc., of Cambrian genera in the 

 Etcheminian strata, and for reasons given below, the writer proposes to revert to the classi- 

 fication of 1889, wherein these deposits are called the Basal series (of the Cambrian system). 



It has been found that slates with fossUs of Cambrian genera are included in the important 

 group of volcanic rocks which lie at the base of the Etcheminian, and that where the dip of the 

 48011°— 12 10 



